Field of the Invention
The present invention relates to a recording system, a recording apparatus, an information processing apparatus, and a recording control method, and more particularly, to a recording system which includes a recording apparatus having recording heads mounted therein and an information processing apparatus connected to the recording apparatus, and a recording control method used in the recording system.
Description of the Related Art
In general, a recording apparatus using an inkjet recording head (hereinafter referred to as “recording head”) may not carry out proper recording when the number of ejections of ink from nozzles of the recording head exceeds a predetermined value.
When a recording head has an electrothermal converter (heater) as an ink ejection energy generating unit, for example, heat generated from the electrothermal converter rapidly heats the ink to produce bubbles whose pressure causes ink droplets to be ejected from the nozzles. Such a thermal type recording head undergoes stress, such as heat, pressure, or a chemical reaction with the ink, over a long period of usage. As a result, the resistance of the heater increases, or the rapid heat generation from the heater burns the ink, thus reducing the amount of ink ejection. This may prevent the ink from being properly ejected, lowering the quality of a recorded image.
Japanese Patent No. 3294008, for example, discloses the following scheme as a conventional way of avoiding such a situation. Specifically, in frequently recording images containing ruled lines or the like, the number of ejections of the ink from local nozzles of the recording head which records the images increases so that the service life of the local nozzles expires. To prevent such expiration of the service life, Japanese Patent No. 3294008 proposes the scheme of shifting an image to be recorded in the widthwise direction of sheet for each business form to be recorded, thereby preventing specific nozzles from being used in recording in a concentrated manner. Such a scheme is a technology effective particularly for a recording apparatus using the recording head having a plurality of nozzles arrayed in the widthwise direction of sheet to prevent concentrated use of local nozzles which originates from recording of ruled lines or the like, thereby prolonging the service life of the recording head.
By way of contrast, a recording apparatus using a recording head which ejects ink from an ink passage forming a plurality of nozzles causes uneven density in a recorded image due to the influence of a fine variation in the shape of the ink passage which forms nozzles, a change in the amount of ejection of the ink as a recording agent, and the like.
Such uneven density is overcome by a technology called head shading (HS) as disclosed in, for example, Japanese Patent Application Laid-Open No. H10-000764 as one of correction methods of making the density uniform through correction of image signals or correction of parameters at the time of image processing.
Highly accurate correction using the head shading technology requires that a host should execute correction with the positions of nozzles from which ink is ejected in mind at the time of generating image data. There is thus a problem in that, when the amount of image shift changes abruptly due to, for example, interruption of a job, image shift which cannot be identified in the head shading processing is performed so that the correction is not reflected properly.